"Fatal attraction" as erudite entertainment.

Actresses Cate Blanchett and Judi Dench made their big-screen mark playing British royalty, but they are far from such exalted territory as teachers at a shabby junior high school in a lower-middle-class London neighborhood in Notes on a Scandal, a wickedly entertaining adaptation of Zoe Heller's acclaimed novel.

Blanchett is Sheba Hart, a first-year art instructor at the school and ex-punk-rocker who's been domesticated by an older, college-prof husband (Bill Nighy) and two kids, a surly teenage girl and a son with Down's syndrome. Hart is befriended by a colleague, the aptly named history teacher Barbara Covett (Dench), a self-described "battle ax" who rules in both the classroom and faculty lounge with an iron fist and suffer-no-fools demeanor.

Notes on a Scandal features rampant voice-over narration, which is usually a lazy device for filmmakers who aren't able to convey what they want visually. But in this case, the narration not only works but is absolutely crucial. Barbara begins to obsess over Sheba (when a stray golden strand of hair falls from Sheba's head at a school assembly, Barbara picks it up, caresses it, saves it), and in voice-over we hear lengthy selections from Barbara's diary, revealing the interior life of a repressed character who reveals very little of herself in real life.

Barbara's observations are enjoyably acidic. After meeting Sheba's family for the first time, she refers to the husband as a "crumbling patriarch" and the son as a "tiresome court jester." After dinner, Sheba and her husband dance with their son, who take great joy in the activity. Barbara labels it "a rather mortifying family tradition. They do things differently in bourgeois bohemia."

But she also reveals a longing and delusional quality in these diary entries, and the richness of the movie is they way sound and image rub against each other, setting Barbara's twisted, unreliable world view against a reality the audience can interpret on its own.

Barbara's increasingly romantic obsession with Sheba takes a turn when she witnesses Sheba committing a great transgression, which Barbara perceives as an opportunity to manipulate friendship into something more.

Dench (an Oscar nominee this year for best actress) is riveting playing against type. But Blanchett (nominated for a best supporting actress Oscar) is perhaps even better: sexier and more complicated than ever. This acting showcase that pits two women consumed by inappropriate obsessions is ultimately a coal-black comedy and erudite entertainment. It may be rooted in the seriousness of loneliness and human weakness, but it succeeds as a high-toned take on Fatal Attraction.